SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6b38e95bec20485d8991a12015ab81052e94ac076deaad93912252adfe63037' 
  AND token = 'dxG5AuH5ieyIeITi8vhA65cNfzwUXoyJW1ZGtZvl/K4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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