SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0a81f00ed5fc1cbb70cbfc1aee98a03de75b4fc6001b9f3b16a72b7a153f69b' 
  AND token = 'eks2uUGwiy5hY60izbIlXpzxt/GLNXb5cEpQk+CZtiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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