SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf6c0bf1678f7d100035591ddfd4a848fc53e3aa1beb2cacc19269c8d5a6a28a' 
  AND token = 'QfX9hXqkHttswKJ+KYy5R1FFFFozfVsZGxaI0GW7Glk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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