SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09f1ebad4a6a823c12b235da9d571b68856ccfb8d572445eaaffea9331c6d1dd' 
  AND token = 'R9y2HJ7gRLJtCqYEmTQoY68BGswaV4C5EA4UXZOoC/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}