SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1d8930c4a2ecb65aa3238ed07a0ad6228504bb944a40208063d959b0415f56a' 
  AND token = 'vbnI9y51QxfdQaCZIWL0KYJF0Fzuz4qYhn/CvxoVhUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}