SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54b4439494eec53f2ed1e55446fafbe536734cc92c500f9665a131ac921402fb' 
  AND token = 'AVdNzGZmsre8NXGyWtl7Xpxa6/f9eeKOJzzDRTDLXQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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