SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42a1b79cca4e4c44fd8ea89282b760eb439a71ca5bce94474cc5171ab25cc4b5' 
  AND token = 'exTmGZC1WEX6tATM3XjoYInuNVbVjh4qpEFMEL7IKmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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