SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f61b60d05e5d9c7621ab4ed7782a3883b203680cb47b49760b3e9e5ba9d0130c' 
  AND token = '5/hneaUIiDRZwaAar7bnnV+/p9oEEbFxE31OyLRb+vo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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