SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51482f431b4d6ff097ce99ac328630e447ab27bf49c90fdf97095afec141381d' 
  AND token = 'l34L4KAR53w8seFOhgQaE4apqTRbTWXZuH5dPr/Qhu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}