SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72db96b0fc2349da08a3953bee296a7f64cd99e439fc907218492af679e0ad54' 
  AND token = 'P4udX3FHazNIH02Xcubyfe+Db5V1vPklKuygcJnWBIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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