SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '302cad395fd54ef1ee3ab1847ad080fa90a38ee81327e0137ac16ab0f34f7160' 
  AND token = 'wJVSmLCXMNRn9dyIcVw8wpRKuaOB0UF4XL4oQBtKkFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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