SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8774b19353c5006e8a367b5ccffcc9922e9a15bad9f6fc295502fca6c01a1b21' 
  AND token = 'U4pzH60uiGpyDcOB1yYNjSiBGRxCUE6f2fiuX2FSp5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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