SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbd6cb29b3111e6a8f06dbec81ff349da09039328c8a03a25d8362587fba6398' 
  AND token = 'vAN8Iup9LgRyOLIyUjeEtw89CKdUSxA3qPmdWB+uPso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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