SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76aeea2f1a846c3bac24e7ef12f8ae66010d607d51a16f0ebaa916a738627515' 
  AND token = 'kzZ/9hBgR1+/WqHa2nGs3oSuAzmc5MtVJ3tRvcphCyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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