SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c25bdae3dfa085a8465ac83510792091841dfd920a2c1635ed5f4748d180fc0' 
  AND token = '5P3eEDRAB85ymmjyJZj8pGzffCQjoi+BKrjQWBRbeDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}