SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cea36b42f078989b93674e9238efe239a36b8a715a8e847ca37563fef199d178' 
  AND token = 'PghPlEDAURCEvfb/aJKuJqYeAq5RDUypaBtOK7yaS4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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