SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0341f2ff8f10d186cb5b586dcd74c47b058312698b8c72f5aaa0f7961eb11781' 
  AND token = 'K3wM7Q93VhsetDQ4T+4Hq5ZzwkvAtJ0n3yXGTX3g9SM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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