SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03027bb0e1cc391f17ab3958f9989bef04027cdb7739f382a9170a28e9766cdd' 
  AND token = 'lkWpmtLjogcwuvQe07g/UeJh+ktdQEfg5SZ7S4KcYjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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