SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b77d3749f6b763f00f93efaa3e6a3e808140324f1c95d64511ee52055287c886' 
  AND token = 'NgREVL2JoDeAo5708HoaIv0zV7uVivQyQaa0dJy8utg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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