SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9999bbb42baebc8947c9a1efa9f5ddd3976b7a255ca67b2ac9923f3029a848bb' 
  AND token = '3fCOxZ2zlY5CTZ+GwBDq8EiJaHUnO6pwYtxHNwRNBuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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