SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cadd517c0e307218ee4c1bc7c3cbd55626aa58e27de012bb1bad2c696e7e62b4' 
  AND token = 'clNYVnit0uLjVqgaZrphuvjIiASer9KEU/rjpn+FLAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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