SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4ed933381b4204fc9804ac25db1d26d85e848171cf249bf4b0b5c32d8f7a5a9' 
  AND token = 'ElzPAwD0c27vRd4ZlUKGUf8t03Imh7ca5V+ASraLqnU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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