SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7423988f2de64922fed16a91f18cb8bde2e402c6b41036319691982f7222a72' 
  AND token = '2+SL04hsoNKgWLMHhpiwt7yoxgI6HEjzIN/mJ0TSzSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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