SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bd233bfb0edc0cba165543eae24cbc5e0546cc19e2bb1d407ddd8e8fd6b8491' 
  AND token = 'SiEeIFKDqTrsytjfE0QRXxNQ+rS3jnuluB9ZaRCfyzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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