SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f52a43ad3e0af68dd3b48a282bf8b04753000eb20c614dabcc906129358bf89' 
  AND token = 'tkfis6t1SqrR+eM9dbUGX1Yg1StMb7+dU7HGSznMroU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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