SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc6dd35f0c47a8750d67c15aadba4913a667a27bdac3af9a8d4089813007a1db' 
  AND token = 'wPHG293yVTMDjNWBzARy+6tYkqo8MGguFFwMDOi4ldI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}