SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '796ba5bf405b6a6b6c2e88b8107def8a0ec1bcfc07a326f0b4ab536ee8dfecee' 
  AND token = 'XBkQvva7e/Uws5ko9cEYtjtCPfqArtGTXkqTKlhNbtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}