SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ad169371df8f0dc6b56448f3a37f12f3e38d4135eda99a717ed0418eb013950' 
  AND token = 'xnK/LyCSSCsMunaiHdTGT9o4HgUmWiFrUbsEEbl5G4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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