SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '747893f2355cdcfcf23e111eda9d7a4556f4eb69784ac344d79d93023a2b7fc9' 
  AND token = 'Ln973uDBPTWjYFyuGaryMDQdcVBBldwau8iFbGtvm4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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