SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce1cb9a48e2bdffbcc8f3faef061af60fdb950d4accb3ccee6a52d7fc49463b2' 
  AND token = 'n/I9SEGYkLzCRuLVDuU2qgRRLKoiffhIjTKVlHvQFzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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