SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61ef3c329547305a0853d8fb50a8820b965becedf66d65661bc516572885838c' 
  AND token = 'PtgDzSPnR7xhQ/8UMR2BGHrpQUlZs2KpqmMV3kvEkYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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