SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0253b9e26f3cbe512e26c4a38a8e339013ff63442800006bd78f06e2917eddc' 
  AND token = 'eHzaGQfWiUkYPpWqzlMBqVaLhRlQXKcxn0w979UjetY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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