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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c77fa936f756ef0ee5584e613b73e4f81af2c151e0efaf9674e4f4c5c151941b' 
  AND token = 'Dt+ejtZ3DTYQpa3fXEFUYRE9kPmxzvnUPYJn+T5Esyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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