SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37da227d956f0ce9ba4fa097e599188a84b0c6545451cdb0d7e9bdf969596038' 
  AND token = 'G+a52VveSIxzrtwpwKYAdLuqooHsCAWBzNVTjOiZhZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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