SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b15c86cd38a82526cecb8c5d81efc8bae55aaa6cf87ac7dddeacad78f2e10024' 
  AND token = 'w6XeWGQWwQMBxcOB9AnV47zt8uJY2lGYRtTYuzwTC60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00068

JSON explain

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