SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '284248916e142612b6a375f8ebc1d99471b0a71044eef1c4674a273fe754b69b' 
  AND token = 'P1zyjX2EGRsGBz1ySjfq+0eaHplQLViGsfWZrQhh/Ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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