SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f3df71467de67c3aec16f5aea6a73eb2fed6adf279f5146ccda815ab02962fd' 
  AND token = 'zJF4tYtVnXQ0cNSeWs07Pz8v2E2yCmk7mniQYssp6iY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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