SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '529dcd5d71418d5f79182fee188ad57981d1a2895690a1685dbfe3d280413821' 
  AND token = '2Zyvo9EmFWXTjPLUJPj+HQwPcmdnQOuyPPzR/qYYaJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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