SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4704a860824561007f9df088d15b27863292c7a1ed2d6440e0b66992b110e2c9' 
  AND token = 'tz/Thps6G6I2ZoQfA5kZHY6ighz3jARHO0E0MCNpsLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}