SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '814aeeaa2565a9f17822a117899e2f5f510a7090395b82d4141a82a678ea9a27' 
  AND token = 'JXJJv5oObLgYYrlHMhcpep7A/mHi0bzrosJkTlSe8EQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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