SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fc499ec54b0bc20fc966aafe8086d2e5236142205d1f6f743f6754d66122833' 
  AND token = 'oRKJ8vJZ3lnK18jZ1GJtqwMGnWKOYMImfrbdfKgAjDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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