SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c43db88e0a65bb5c4057888428bc4556befb8b72c75ee1086ab5b3188d494349' 
  AND token = 'WKLgN8CKK10zfVwawLztuMiINHZ9Ro89UNVxpUY4i90=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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