SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e53385bae86fdef1123e60a7081315295fb13fdb7e63e5521271a150511c792' 
  AND token = 'l9ZjOdX9GuWLzVrOm0IW4F7YJO2M+gs4FaxcCXjq2Z0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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