SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c187c5ce286b7ab960c7e8a61fd323e23199771df22788fda54950d43131a76' 
  AND token = 'OmgUpWmuUsIt+Xd3tQcSsQrTZeCAxdRRn2vza72bLeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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