SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58d0b9aecea005c8faefacd1ba27b527f434bf3abee15c93a0d05a24343783b2' 
  AND token = 'PpZ961JPxSXTyOBJGBs8qXt92jURFuFB28cYXyCVYoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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