SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '484269219a7e6ad9e3faa64f2bdb92bfbee895d48d32d947522df25a47d85b03' 
  AND token = 'hs4Mo8Y346oqmid+T4zOHI+Ft2NEsC2dz42p/XdYofc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}