SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3402f8188d2260cd4566220de944b9c215845fab79a401b7f60e712060329e7' 
  AND token = 'IIB34KHuDp6rhtDH/1FYtPmjgT9w6zDLKss5nVDnw5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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