SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f48307bc2e8cc011efacd185fbc72b770347c03d39a44d6a27cf5062d5feb87' 
  AND token = 'pJ2anUYXCqbmyxuWrEGeAXLzFfOh9Oas/ITj3dRovNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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