SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f0675903779ffe37a49a5803e6459ac91f5469be85150d6bbed7efe1567e3d60' 
  AND token = 'flU3qpeh+SQWN9Nt+aAPD883N82aRlYreCMe00vs6WE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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