SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd15f39f04a7d550ea5af3ae141228e480d4599db1d9d27a4ee25de0e4815f585' 
  AND token = 'Z/+zeRgjunboGMBVZA7/1z70tjwMfvUw9zP3zmg7dO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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