SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd275d6368a39664ef55aac9c28b969453b20e10b9ff6c79fa1b11ffbd45b0bd' 
  AND token = 'pcA/JYO+X5uRq4PKRZxivWK/UXkzEUx8V2IBtz/UKp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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