SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea77b05402aec30652639ca702a919d54b89ed2c76ec1db4a1a0d51fb3e0dc21' 
  AND token = 'yVWJML+qQmwXKR9/Voc6FkJgVetKqNBgnWIZ4mdI84Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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