SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70a54e6391a33058a6294d197607d6fbdaaf78d600f569b22fd2f3079590cb96' 
  AND token = 'JBKn2xQQN5TnswwIWS8yBLDAzFk5yWh2Xhz+ChT4he0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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