SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba07c4a3f4ce5a476e9cda1b81edef4e975e2536b010009b7d422fe142b881c4' 
  AND token = 'p5jkqZiIJXilyOYftMlsunTUyT9PfTehvcbLJwIv8wQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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