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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7f53efd70a13f8264e3171400c8fd4a068fbd3d58a1e9cbba96ab4dfa681152' 
  AND token = 'Rp1ar7MpLzXLUp5+YpSkpK+1JnBkB88Be9/y1xFybMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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