SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f343d0b40368002c537564b724a3269bf2daff81112721e5a815c42ec4e058c9' 
  AND token = 'kfxUanvWySn0Q5vchmtU2/ZOnD98lHp8/e4EgaaQlIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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