SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '371eb4764d36d7c2a09e0de650c10a1b5cc4b13fc455940b179fe5a1c90e709e' 
  AND token = 'khKOlDQrsBvs/m4Prujnu7YtxbWBY0NkH54eJH3fmS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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