SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9758751565d7c4813eb76e989b2498ce23b97919dab38f5fd9cb3ae77b95ce42' 
  AND token = 'af/TmpT5HxvaKzxwBq06/tvMY6H8efTMyOWaXjipD9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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