SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '534fe98b65ba1c8937bd24b19e190f337a52fdbd021ed0ec61cec5638689e1cb' 
  AND token = '+4MLqfCMLfkWPUgNWF98iiX3FtEP2FAiNjkAgK/cAMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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