SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1f3ad835446a6e5884e514dc0fb5f4b560d0524246313d495ef33779dabf830' 
  AND token = 'x63nFPfli3a6NoXbC0c+wtYrdDIUeVLddmpLz//77TU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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