SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '420abc8f8de304226f0c36e2f186d124e464b28654b68a8806cbc0437ca59cec' 
  AND token = 'A5dp/OSCcL5mbALe39dUjd5S5DY0HeFinPv9CTkk/mw=' 
  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"
    }
  }
}