SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a9f5fd5b8157939d9c3ade77d3f37528056cc08cf8c4ed504091fd0b76227cb' 
  AND token = 'KWSMsaf89sGcaPN79wrjHiFTSwR2YfYeygJBmCcPEIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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