SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cbcbf1115ffcd7d56cf99384c1096c82e78260d33c86b22b6574dc2350ef311' 
  AND token = 'BVPEJ6PdxiqFSask6OCdSGk9+Q0rLFQWYUoqIfhjGB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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