SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66b6bde78704be8c96ae90c448619f2bf69cd76bea52aa133eb2b5181785ad91' 
  AND token = 'torIFeb5Spwxd9QDfKhSK7gDj27DWJAlgILdKL1pw8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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