SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a54b79172306a6a080c9e5ce2d58e72d2c414ee81aa32994df65e4a29f58f7d2' 
  AND token = 'nU/Rmb+mdYonN4RsHYP3BMJ8xDLf7LUQqhCpD7BVkZw=' 
  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"
    }
  }
}