SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c37cd44a693f63beb757e626de1bf6443a2c6f801acaccffe88f97ff3121ed9f' 
  AND token = 'kM8znVBppo+PHSLWnGA0QJRsGT0vtlUXllZUtjGAe/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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