SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1d6a8f1c6b707257c223b369df74870f7920827e7edaae72526c6e8f58064b3' 
  AND token = 'pbe7vKIItVqPbYBpyMbjw0h94LL5+Anx2kDrH5uKMDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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