SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2fe691dec19425c84b1a86eb3491c1ed760312abbb8b11f7e41984c4a91c2aa' 
  AND token = 'tUc6GD00bsx70c3t4oaDPeTFhmnnINu1fAjZyYtHfaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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