SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28235d289771e74e4b7cc9e6cbee9d50c4bcc7705f66a64f894dd4028e1ccfc9' 
  AND token = 'nWs+/qJK4mXx5JJj1/waqkMtLj+UXyhv0a4nUpOuVjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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