SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5271ca4a41a40b3e38343f0a670eccc13cbaf9e8a6af9d1443cad125c97424bc' 
  AND token = 'LUIp1VUXwKEX1fv/XQWGt685hZiUTLpNJ8EuxT9bgnA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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