SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39c48906e2d501adb4aa247f5ffb33c9a36089fe53d0574bcc4cc6fc9995521c' 
  AND token = 'ryjGq5VkHXOD5PwV1APdBBwn9wJY5r5kroeqL4K0Bp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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