SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0714c84d3c8f72000047d8d700506996d42b122383ffe3cea6efee9e5a7e6a51' 
  AND token = 'bWoXinErMVEa9IJljgWaaxylFzvIXBEZZHH08VwhCUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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