SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5129cf1d096896fdb2217ba879c50316476e4e3100d0fb5a3aea036ee350170f' 
  AND token = '2vmnL9p2JEsG3fQVw1GBqFPyWl1rYLbpSA3AVbpkpVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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