SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28c354a5be3286f311410780d4c946c2eba373d26a47047c87f6ea948ce53802' 
  AND token = 'lmVu+vNDUToXDHGXcESW/xQfOBhTQMPvoTrFJba5K0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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