SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16e29b9e89bb6b88773d153e4ee21fa81d8a068ec915ee5973cc516b3fa16774' 
  AND token = 'v02EHfpH3npedgdt4AuIoZLZ6kjctKyd+sPxUGGdcPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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