SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5f6586a93c5478ea6ee5bd39c867455181786b994760d999e29a1f9381a2f7e' 
  AND token = 'xY0SpyDNHUDoDGiFcDt15bwq8DnBbbSsm7vF+ffUMWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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