SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c5c0d48622d94fb1709a714d134a3d07ff1225af847f3d9a8c6569fc4113e78' 
  AND token = 'FEiWw/sMpKcJtpLSlRxgYRSe0RxRw0EZUadj7n/mOmw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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