SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '338aef7e9f7c2dd2d3cce46330ff34ed970cee7987f9278389d54c03beffa95e' 
  AND token = 'VgOT9m5LRbA6adxeLlumgjBCQPr8qbgv1uknK8KjREY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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