SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '746a17e4bcc37e76120038307e0f7419f2457d7fefa261ef82c15406f71304da' 
  AND token = 'RIUQZOfzc5EVjqcBuZhIg4jBB32cq8sI6Io4waWRDzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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