SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20b146d1cbe0f41ff607975be911427ffde312d25d05349cc7c57d0e76a260ed' 
  AND token = 'tbunWVrhqSVjJry1yMxEGwnQU38m3TtAleYyEHoBq94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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