SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd70678f7d7f84458797170eaf7ec3fb8a6f77592408385250ccb687274299459' 
  AND token = '8tCqLvmRTR85DVAaLC+8prJCUU3e3DK4ES3ChRTGYsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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