SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75bede27d81cc510e7f1d67411371c35fb6a01e0eb1b7cd19711432481b1598a' 
  AND token = 'h8OfFYvGWzBJ+fUmutBqKxTqDP7BNPjw0N04h1z+FY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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