SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19e70783affca16b5d46aa892592af0bd6f3402f664a5ce88395ea3d78bdbb49' 
  AND token = 'dZ48V4pNV1Gj2L/9D1yfH34ZqrKV/P2JxiKCxQqP0/w=' 
  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"
    }
  }
}