SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3d256556fbe0f603e122d1979b75a26e83a02b5e565e296bf5376a5cd3ee53d' 
  AND token = 'v22Ty0HxuKy2QPnDAMrU3MLme0HtTSShjqiJC7EkLLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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