SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9be814b67d7d79af9237b1be8fac76111f7a61085b741cf2261250e5327def4' 
  AND token = 'JnFz+bJhvTGJ5CtOKmyx5G/UfPZDTXr250DLvXsKENo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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