SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83817a3ee298c5aeeadeee051b03f43a6b0c873d3aded778a0344d89fffcd3b6' 
  AND token = 'WeHxkLBjjZxX1BA+V5mYVggFpdG1N4iOg7U/dKv3v2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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