SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd08fed0e88821460140959e6860fd760d35204fd1d6328e2a768198ec9f99f3' 
  AND token = 'QnLP6+8yvBYWwy5BXKN3al0jFV7J7JmqPpjigDjm0qA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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