SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74e793863e289d7fcc4cdbac64ed9b04b82bc3d48da9d945d0a62b963304a110' 
  AND token = 'iamgkH1AywUEByv2N2JiD3KjpHhsXoFnhnxGNp4kwYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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