SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1544b3803d0a2a108798401ecd60ab37d7fc8612b3e7939350f6212e67d419cc' 
  AND token = '2zJsyBzCDMPwsL1yQXGOgQEqH5u2F+mZWWU3v/94xB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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