SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b136455cf4a5fc6b666530a3cb18b750b0d7eceddcf95890552a1fa52983e8d7' 
  AND token = 'SNnQYg2WArD5JQKwKoCxCCfYWWwx5kTAwuE3lu7XWa4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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