SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5138710d024b25b513bdbcddb6725c47bf34aa856711411ff141e9f5a6f3a937' 
  AND token = 'yosqIghQCSOatTCEH2HsYV5R72QLUrAThZ+TWht9jAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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