SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f86183a8176904cfa964355ca3376158068abec1d8c553333db94928b526db83' 
  AND token = 'eT9rPN/jpahQvCpZ4el+Ur1daLhWgFqXApZLanBSDuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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