SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7df91d19915f7b7d7991cd96962809a8453c4f1fd0e0c2b7c66e005d5e43f3e' 
  AND token = 'a4Et4jyRpsCtUSzitz63VmHy4CLcoxEDcx9JWhEi8bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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