SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1dde50cebab1638527b95ec45d8c53e29c7eab5e7bc05d8cddb79ed95c788f1' 
  AND token = 'W7KjyxmuxV+/wbfJnUNc11eKJWc0O4WsmcFB5eeuSPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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