SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd67e31845fd4d454525e6fa0e08a19eb8f52c4caf0e2cc8f825f40e493ce2500' 
  AND token = 'exvmNgWrequUJhfZAXd5dI8/lMO0fpB8AagqgH4jqYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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