SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c136d935970b02ffd8dc6f79450f9c2bf49ea3d2eae9c11c8d9c6199e4eae4b' 
  AND token = 'qqQh5Bkl5BegQlZ6iH+GaMfDKxe+YXk1Z4mPFvVi1oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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