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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee6b1aac562a2284233f78e795bbe5bc81a3d6642994fdab6d47057f64ac2344' 
  AND token = 'MTEx22ORFcAeZHh1c5ur2jyppDzFYZb1L/vf/2c9IKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}