SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fae98cb940e96296a3c00123b322087d4bc50983e68329da79105ad18c4df517' 
  AND token = '9KV03l/8pYmXgHiphfgkJCu3BhZheDXi4M/YT7/Md8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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