SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2e832305d68718d7c9d30eb79e73fd40e74663825c72f95e0eee16398fb97b6' 
  AND token = 'ofmTCEdLaNywSn6eNak74BhpG+1kTNBR16xFxTkkujU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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