SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8cb3524efceaa948fd72675d5b9c8e7f12d0680e16357a2809e2fdec38bf44b' 
  AND token = 'b1Nxvuz/HsZ5YyKJhmxMhXoVI0y851ljV8H33K4knvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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