SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4cb5095529edb597fb3bbe3ecb4d1815a8b3920967d980db6b7a70427310536' 
  AND token = 'WsRwXZ12szoRaFFrFucQpgmeTHV2bB0i+nK0kKFZhEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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