SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a9f63b6575d717c50ae2a6fb92383498a73162588b6ae0ce3521076e1149943' 
  AND token = 'Hjejs9X6v7EL2VSPOGajLBHxS4wYuCXIiBWdHpZ+r10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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