SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e7c4c61121ce9434759b8973ba64076eaf8ab608b072ad0aa93b049cea76465' 
  AND token = 'bi+ztCVhbFdXzoTf4JUTWc6qbQYCcHAXPP4Dhtsb3Y8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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