SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '172fb61e386694a136a35745784d6994cde801e9e6436d05c5f3760b27480b1b' 
  AND token = 'eKS+BIvITjuBC5Gi8LFskb+MNFz1roBxuYxNshFGIp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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