SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86866e50c6f409693103e4cec37357fdef7a2bb6f25359730624845af5c34de0' 
  AND token = 'oqqjpgeuEDDdsr+fmFEnotZIzQoBCisnbj4lVVVAsv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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