SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f644536a7a27b7d48f9637a7efd5c637378ef6f0797bd0411de3953b2f7399a9' 
  AND token = 'SlJZZ+I6VSfWMUm6Hk5/5KhXwSMymniDvXlVPy1ftYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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