SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8731594ec01689a5c2c5049f8e540e46a30ee52a8867d340aa648a470456df12' 
  AND token = 'rI3HqZZLBnBqV11BAU5dXSbRpsa9nGbYRXPbnWSW2Js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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