SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0875237502ce67811988dd7a04f0aab9d4a4bd396f49821b4b6201bc00ba765c' 
  AND token = 'I4JD5iRYxfj77FR+Z1Jq1VketGRMKD6TYRmAZUSLsCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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