SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db310380556b674bcdf4f6d69f35ad37f162cf6cb859b816bb9c00472de4ba44' 
  AND token = 'eKWMQQ+gDPziiiMve1FFODuKG3lu9jrGxt4bdzt88ro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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