SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03ad35f5b5538ca14450b8742d91959ec52d33184371fc5213042b028e6c73e9' 
  AND token = 'zHvZeG+MiyFOhCkzoYZY4tJ2gToGaVUEsl0VxfIsx28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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